Most of the research on the effects of physical activity on health behaviors has been conducted in the United States (US), Canada and Australia, where nationally representative samples of youth involved in organized, school- and community-based sport programs are compared with those who are not active in such programs. The positive effects of these types of organized physical activity, which in this report will be referred to as ‘sport’, are well documented and reported on here. In general, there is clear evidence that youths participating in competitive sports programs are more likely to eat more healthily, be of lower weight, be less likely to smoke cigarettes, or engage in sexual activity. In addition, sports participation has been shown to be associated with less antisocial behaviors such as drinking alcohol, use of illicit drugs, and engagement in violent activities.